(a) Field of the Invention
The present invention relates to an organic thin film transistor array panel and a manufacturing method thereof.
(b) Description of Related Art
An electric field effect transistor using an organic semiconductor has been studied as a driving device for the next generation display.
Organic semiconductor materials may be classified into low molecule compounds and high molecule compounds. The low molecule compounds include oligothiophene, pentacene, phthalocyanine and C6O. The high molecule compounds include polythiophene and polythienylenevinylene.
In general, the organic thin film transistors based on the low molecular weight organic semiconductor materials show a high mobility in a range of about 0.05-1.5 cm2/Vs and superior on/off current ratio. The formation process of the low molecular weight semiconductors layer, however, is a little bit complicated since the vacuum deposition processes are used. And as a consequence, the low molecular weight semiconductors have a demerit for mass production.
On the contrary, the organic thin film transistors based on the high molecular weight semiconductor materials show rather a low mobility in a range of about 0.001-0.1 cm2/Vs even though they have a merit for the mass production due to their solution processibility, such as coating and inkjet printing process.
Recently, some organic semiconductor materials show good processibility or solution processibility as well as good TFT characteristics such as high mobility and on-off current ratio. And some semiconducting materials with good processibility and good electrical characteristics are developed for the top gate structure even though many are developed for the bottom gate structure.
Organic thin film transistor shows photoleakage current when it is exposed to the light so the organic thin film transistor with a top gate structure cannot be applied to LCD display even though it has good properties because a backlight unit is used in LCD.